In the early days of communication we had the phone-book to aid us in our quest to find people. When the internet was first conceptualized, developers used this simple concept to build an intricate network of connected nodes. The result was the DNS.
What is DNS?
The DNS or Domain Name Server is a globally spaced hierarchical database that keeps track of the address of each host name. For example, if you want to contact google.com, you will query a search with the domain name. Just like the phone book would supply you with a person’s number, the DNS too attaches a number to each host name by which we can contact them. This number is the IP Address of the website and it is crucial to know an IP Address in order to send or receive data over the net.
However, since the DNS is a very old and simplified system, it lacks the basic tenets of network security. As a result, construction of DNS firewall is essential to prevent breaches in your network.
Let us take a look at the possible ways hackers may steal your data when you are negligent with its safety:
Zone File Compromise
A DNS server is usually configured by network administrators to be able to access its zone fileand resource records. However, if security of the zone is compromised, a malicious third party may gain access to the server and reconfigure the zone, thereby compromising your data. Such an attack does not necessarily come from an experienced hacker. Anyone with a basic knowledge of DNS may corrupt the system. Thus, it is imperative to limit network access only to authorized admins and to erect firewalls so that external agents may not gain access.
Zone File Leakage
Your DNS server contains the names of computers in any zone via the DNS Zone Files stored in the system. If an intruder gains access to these files, they may deduce the server roles based on these names and thus deduce which server can be accessed. In addition, if network information is also compromised, the attacker can gain access to unused ip addresses in the network which can be used to set up a rogue DNS server and gain control of your network.
Dynamic DNS Updates
Dynamic DNS updates are used to automatically create records for clients and servers in lieu of having to do them manually. Of course, the added convenience also brings the added risk of breach. Dynamic updates are usually of two types – secure and unsecure. As is evident by the name, unsecure updates have minimal security since the nework allows any host to update DNS registry. Thus if a hacker gains control of any host, the entire network could be compromised. Secure Dynamic updates on the other hand have some form of authentication in place, but a skilled attacker may be able to bypass them if it is not secure enough.
Denial of Service Attack
A popular method for hackers to corrupt your system is to launch Denial of Service (DoS) attacks. Plenty of botnets exist that can launch a distributed DoS temporarily taking your network offline. In the meantime, hackers can set up rogue network and intercept any traffic guided your way.
One of the favorite methods of attack for hackers is cache poisoning or spoofing. The DNS resolver, in order to retrieve faster queries, keeps a cache of recent results. If a hacker gains access to this cache, they can configure the resolver to return an erroneous address which can redirect traffic to the attacker’s computer instead of the correct destination.
In any network, being able to keep your data and resources secure is a key to success. An attack can not only compromise sensitive information, but also ruin the system structure which will cost time and money to repair. Prevention is the best way and by setting up elaborate checks and firewalls you can only protect your data better.